WCA May 2022

Technology News Quality control in automotive extrusion lines

For more than four decades, manufactur- ers in automotive cable lines worldwide have used Sikora’s measuring devices to ensure the quality and dimensional accuracy of the core while reducing material consumption to a minimum. Sikora offers two models of the Center view 8000 for different cable dimensions. The Centerview 8010 is mainly suitable for the measurement of small coaxial, data or automotive cables with a diameter from 0.25 to 10mm (0.01" to 0.39"). Optionally – for micro coaxial cables, for example – the system is available for diameters from 0.1mm (0.004"). The Centerview 8025 measures larger products with diameters from 0.5 to 25mm (0.02" to 1"), such as thick battery cables, which are increasingly installed in electric cars. The Centerview 8000 is flexible in terms of its position in the production line. As an alternative to the classic cold measurement at the end of the line, the gauge head can be installed directly after the extruder, and before the cooling section. This allows fast measurement and control for production efficiency with high quality demands. The system combines optical and inductive measuring methods. The inductive measuring circuit measures the exact position of the conductor, while the optical system measures the outer position of the core. The optical part is based on the principle of diffraction analysis combined with pulse-driven laser diodes, which project an image of the cable on the respective CCD line in each measuring axis. Two optical systems measure the position and width of the shadows over four axes at eight points. From the position of the shadows in relation to the inductively measured position of the conductor, the eccentricity is calculated within microseconds directly in the gauge head. From the width of the four shadows, the optical systems also precisely determine the respective outer diameters and ovality. circuit automatically positions the gauge head so that the conductor always passes through the centre of the gauge head, where the measuring accuracy is highest. The system also independently detects The inductive measuring

Sikora’s two Centerview 8000 models

measurement on the Ecocontrol. The scatter plot, which consists of a total of 5,000 points, graphically shows the distribution of short-term fluctuations in eccentricity. Each point corresponds to a single value of the eccentricity with respect to magnitude and direction. The extent of the scatter plot characterises the standard deviation of the eccentricity. This visualisation enables the operator to recognise which eccentricity values persist even after optimal centring, and which fluctuation range is present. The Centerview 8000 can be combined with the hot/cold control module of the Ecocontrol 6000 or 1000. The module continuously calculates the material shrinkage and automatically takes it into account when controlling the diameter. Sikora AG www.sikora.net

and automatically compensates for slanted positions of the conductor. This eliminates the need for guide rollers, manual pre-setting or readjustment of the system. The Centerview 8000 is available with an integrated 7" TFT touchscreen monitor on which the production data is displayed. Alternatively, the system can be connected to a Sikora Ecocontrol processor system via common interfaces. By means of a sectional view of the core, the operator receives a standard display of the eccentricity, enabling the crosshead to be centred. The low exposure time of 0.25μs allows the Centerview 8000 to capture oscillat- ing eccentricity values with a high single value accuracy. These are displayed in the form of a scatter plot, which is an alternative display mode of the ongoing

22

www.read-wca.com

May 2022